NCF sensor coated with CoFe1.96La0.04O4/LaFeO3 heterostructures for room-temperature detection of liquefied petroleum gas concentration

Liquefied petroleum gas (LPG) is a highly flammable fuel widely used for cooking, heating and transportation, making real-time leak detection essential for preventing fire, explosion, and suffocation hazards. In this study, a room-temperature no-core fiber (NCF) sensor coated with CoFe 1.96 La 0.04 O 4 /LaFeO 3 heterostructures was developed for LPG detection. The heterostructures were characterized using XRD, Raman spectroscopy, SEM, TEM, XPS, PL spectroscopy, and UV–vis spectroscopy. Experimental results showed that La incorporation and heterostructure formation refined the particles size, improved surface accessibility, and modulated the electronic structure and band gap, thereby enhancing LPG adsorption, carrier redistribution, and the refractive-index response of the sensing film. Among the investigated compositions, the 1:1 CoFe 1.96 La 0.04 O 4 /LaFeO 3 heterostructure exhibited the best performance, achieving a sensitivity of −2.87 pm/ppm, a response/recovery time of 36/69 s, and a limit of detection of 39.7 ppm, together with excellent selectivity and stability. The effects of temperature and relative humidity were also quantified and compensated to improve detection accuracy. These results demonstrate that the proposed sensor is a promising, low-cost platform for LPG leak detection in domestic and industrial applications.